A systematic study of the valence electronic structure of cyclo(Gly-Phe), cyclo(Trp-Tyr) and cyclo(Trp-Trp) dipeptides in the gas phase.
Phys Chem Chem Phys
; 23(47): 26793-26805, 2021 Dec 08.
Article
em En
| MEDLINE
| ID: mdl-34816853
ABSTRACT
The electronic energy levels of cyclo(glycine-phenylalanine), cyclo(tryptophan-tyrosine) and cyclo(tryptophan-tryptophan) dipeptides are investigated with a joint experimental and theoretical approach. Experimentally, valence photoelectron spectra in the gas phase are measured using VUV radiation. Theoretically, we first obtain low-energy conformers through an automated conformer-rotamer ensemble sampling scheme based on tight-binding simulations. Then, different first principles computational schemes are considered to simulate the spectra Hartree-Fock (HF), density functional theory (DFT) within the B3LYP approximation, the quasi-particle GW correction, and the quantum-chemistry CCSD method. Theory allows assignment of the main features of the spectra. A discussion on the role of electronic correlation is provided, by comparing computationally cheaper DFT scheme (and GW) results with the accurate CCSD method.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oligopeptídeos
/
Peptídeos Cíclicos
/
Fenilalanina
/
Triptofano
/
Dipeptídeos
/
Teoria da Densidade Funcional
Idioma:
En
Revista:
Phys Chem Chem Phys
Assunto da revista:
BIOFISICA
/
QUIMICA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Itália